With an increase in the industrial and medical use of radiation, various studies on the effects of radiation on the human body have been conducted, and particularly, cancer therapy with radiation has received attention. It is known that high doses of ionizing radiation cause DNA damage, genetic modification, and diseases, including cancer, but a radiation dose of 200 mGy or less and a radiation dose rate of 6 mGy/hr or less inhibit cancer development by activating immune responses.
In general, studies on the relationship between radiation and cancer development, particularly gene responses to radiation, have been conducted, but confounding factors have significantly affected the results to reduce the reliability of the results. However, most studies conducted to date could not explain various responses, which occur in the cells, tissues and organs of the body in the body stage, because these studies were performed using gene-modified cell lines or cancer cell lines. In other words, because gene responses were evaluated using general mice, a variety of genes were expressed, and because cancer development was not limited to a specific organ, it was difficult to analyze gene responses.
In prior art methods that use cells for cancer research, genes were modified, or cancer cells lacking p53 that is important in cancer development were irradiated. For this reason, there was a problem in that the results could not be applied to individuals, because they did fundamentally differ from the responses of normal cells. To overcome this problem, studies on the effects of radiation on cancer development have been conducted using mice having a gene similarity of 95% or more with humans. However, cancer incidence in general mice is very low, and thus a variety of mouse models for cancer research have been used.
In prior studies, a variety of methods were used to screen glucose metabolism-related genes sensitive to a low level (0.7 mGy/hr) of radiation. However, genes disclosed in the present invention are not yet known as genes sensitive to a low level (0.7 mGy/hr) of radiation. Technologies prior to the identification of the profile of genes according to the present invention are as follows.
(1) Cancer cells are characterized by activating glucose uptake and glycolysis (Warburg O, Science 1956; 123: 309-314).
(2) Activated glucose metabolism inhibited p53 activity in thymus, inhibited puma induction, affected the balance between the expression of Bcl2 family proteins and the inhibition of apoptosis, and maintained cancer survival (Zhao Y et. al., J Biol Chem 2008; 283: 36344-36353).
(3) Apoptosis increased in the ileum of Akt1 knockdown mice irradiated with ionizing radiation (Plastaras et al., 2008).
Accordingly, the present inventors have identified the profile of glucose metabolism-related genes sensitive to a low level of ionizing radiation.